Clostridial disease management is a common topic in sheep farming with most of the UK’s flock vaccinated before lambing for prevention through passive transfer, but it is not given much thought by calf rearers.
There are multiple clostridial diseases that can affect cattle, however, the most common type of toxic intestine infections in young calves is caused by Clostridium perfringens. These differ from other scour-causing pathogens (E. coli, crypto, cocci) in that calves rarely show any signs of ill thrift and may not even scour before the toxins enter the blood steam followed by inflammation, shock and cardiac arrest.
What are C. perfringens?
They are gram-positive anaerobic bacteria commonly found in soil and water but they can also occur in improperly thawed colostrum, calf housing and they naturally occur in the intestinal tract of adult cows where they can be passed out in the faeces. There are five different subtypes of C. perfringens that we should be aware of.
Why do they affect calves and not adult cattle?
C. perfringens live and multiply off sugars and starches in the small intestine. These sugars and starches are digested in the rumen in older animals whereas milk feeds in calves by-pass the rumen, entering the abomasum than the small intestine.
What causes an outbreak?
C. perfringens are naturally occurring in the calf’s gut but harmful rapid multiplication can be prompted by abrupt dietary changes, inconsistent feeding or any stressful events that disrupt feed intake.
Diagnosing C. perfringen outbreaks
Diagnosis by postmortem is difficult as the clostridial organisms that normally live in the gut multiply rapidly after death. Infections also display the same signs as salmonella, cocci and E. coli, therefore, post-mortem for diagnosis must occur quickly after death. Therefore post mortem for diagnosis must occur quickly after death.
Preventing C. perfringen outbreaks
There are two prevention methods we can combine to minimalize the risk of an outbreak:
- Reducing exposure: Despite the fact clostridial organisms occur naturally in the calves gut and environment the fewer organisms they are exposed to the smaller the risk of infection
therefore sanitation of the calving area can reduce exposure. - Enhancing immunity: Vaccination of cows before calving can offer the calf passive immunity via their colostrum giving them at least 12 weeks of protection against types A, B, C and D. Covexin 10 covers these four strains as well as six other clostridial pathogens.
The 5 subtypes:
Type |
Major Toxin |
Symptoms |
| A | Alpha Toxin | Abomasal bloat and inflammation with or without ulcers, necrosis (tissue death) of the abomasum and small intestine surfaces may also be present. |
|
B |
Beta Toxin, Alpha Toxin, Epsilon Exotoxin | Causes hemorrhagic enteritis (bloody scour). Beta toxins are destroyed by the enzyme Trypsin. Trypsin inhibitors are present at high levels in colostrum and transition milk so occurs in early life. |
| C | Beta Toxin, Alpha Toxin | As above. |
| D | Epsilon Exotoxin, Alpha Toxin | Causes severe damage to the gut lining allowing toxins to enter the bloodstream and affecting organs such as the heart, lungs and brain. Opposite to Beta, Epsilon requires enzymes to become active so occurs in slightly older calves. |
| E | Iota Toxin, Alpha Toxin | Iota toxin acts in the same way as Epsilon so symptoms are as above. |
